Tectonic Stress Distribution and Its Effects on Fracture Development in the Jurassic-Cretaceous Succession of the Kuqa Foreland Area, Tarim Basin

[Objective] The clastic reservoirs in the Kuqa Depression are generally tight, and tectonic fractures are critical for improving permeability and enhancing hydrocarbon productivity. However, due to the complex tectonic stress regime, fracture development exhibits strong heterogeneity. [Methods] This study focuses on the Cretaceous Bashijiqike Formation in the Kelasu Structural Belt and the Jurassic Ahe Formation in the Dibei area, aiming to reveal the distribution characteristics of tectonic stress and its control on fracture development through an integrated structural–stress–fracture analysis. [Results] The results show that the stress fields of both the Bashijiqike and Ahe formations display a general north-to-south increasing trend, and can be divided from north to south into three zones: the northern detachment–release zone, the central fold–thrust concentrated zone, and the southern stress accumulation zone. Stress heterogeneity within each zone is jointly controlled by fault superposition, fold deformation, and gypsum–salt layer detachment, with the strongest heterogeneity occurring in the central zone. The northern zone is characterized by low fracture density, dominated by hinge-perpendicular and hinge-oblique fractures. The central zone exhibits well-developed fractures with complex orientations. The southern zone shows east–west segmentation in fracture density, dominated by hinge-parallel fractures. The southward transition in fracture orientation reflects the diminishing influence of strike-slip accommodation zones and local faults, accompanied by the progressively enhanced role of fold-related deformation. Structural style significantly influences stress distribution and fracture development: pop-up structures host the most pervasive and well-connected fractures, imbricate structures are intermediate, and pop-down structures exhibit the least fracture development with poor effectiveness. Fracture intensity shows a positive correlation with single-well productivity. [Conclusions] Effective fracture networks are the primary control on permeability in tight reservoirs. [Significance] The findings provide a theoretical basis and practical guidance for reservoir evaluation in complex stress regimes within foreland basins.